The drying of a droplet of water carrying colloidal particles naturally gives rise to non-homogenous deposition pattern, with most of particles migrating to the edge of the droplet, forming the well-known “coffee-ring” deposition pattern. This non-uniform deposition has posed technical challenges in ink-jet printing, DNA/RNA and protein microarray manufacturing, and in combinational liquid biopsy analysis methods such as fluorescent microarray, infrared spectroscopy, and Raman spectroscopy, as well as other applications. New techniques are needed to eliminate the “coffee-ring effect” to increase the quality in printing, microarray fabrication and analysis, and in advancing liquid biopsy analysis sensitivity and accuracy.